Sabbatini's approach on the water-protected 18th on the Hyatt Regency resort course was just 3 feet from the pin. Playing in the last group of the day, Sabbatini finished with a 5-under 67 for a 14-under 202 total.
'I was happy to break the deadlock. It'll make it easier tomorrow,' said Sabbatini, who hit a sand wedge downwind from 124 yards to set up the tiebreaking putt.
American Jason Gore had six birdies and an eagle for an 8-under 64 -- the best round of the day -- to finish in the five-player group a stroke back.
Taking advantage of morning rain that softened the greens, Gore had three birdies and an eagle on Nos. 5-8 to make the turn in 30.
'I got off to a great start,' Gore said. 'It helps to do that when you know you've got the tough back nine coming up. Having said that, I left a couple of putts that were short.'
Gore was tied with Australian Adam Bland, who chipped in from a bunker on 18 for a 65, first-round leader Michael Sim (65), two-time champion Peter Lonard (68) and New Zealand's David Smail (67).
Second-round leader Adam Scott had a triple-bogey 8 on the par-5 12th when he missed the fairway, then the green. Then his attempted chip up from a hollow came rolling back down to where he hit it.
Scott finished with a 72, including a birdie on the last, that left him in a group of five four strokes off the lead. Defending champion Nick O'Hern (65) was five behind Sabbatini.
On the 395-yard par-4 13th, Gore hit a massive drive, and a lob wedge to 4 feet for his first birdie of the back nine. He made a 2-footer for birdie on 16.
The Californian won the PGA Tour's 2005 84 Lumber Classic and finished second this year in the Buick Open. He shot 59 in a Nationwide event in 2005 on his way to his third straight win on that tour, giving him an automatic promotion to the PGA tour.
'Those thoughts about another (a 59) came in, but they quickly escaped,' said Gore, who is vacationing in Australia with wife Megan and will play next week's Australian Open in Sydney.
Little-known Australian Ben Burge, an early starter, took advantage of the morning showers to make the turn in 29, putting him in range of the course record of 63 and perhaps a 59. But Burge, who has won three tournaments on minor Australian tours, bogeyed three of his first six holes on the back nine to finish with a 68.